The daylight requirements in Derry City and Strabane matter to anyone proposing an extension, infill home or apartment scheme in this district, whether close to the historic walled city, in Strabane, or in the wider rural area. Since planning powers passed to Northern Ireland's eleven councils in 2015, Derry City and Strabane District Council has been the planning authority, determining applications under the Planning Act (Northern Ireland) 2011. Protecting the daylight, sunlight and privacy of neighbouring homes is a central part of how the Council judges new development.
What sets this district apart from most of its neighbours is that it now has an adopted Local Development Plan Plan Strategy. This guide explains what that means for daylight, how the relevant standards are applied, and when a technical report is needed.
An adopted Plan Strategy: the LDP 2032
Derry City and Strabane was among the first Northern Ireland councils to reach this milestone. The Council adopted its Local Development Plan (LDP) 2032 Plan Strategy on 10 July 2025, following an Independent Examination held by the Planning Appeals Commission in autumn 2023 and a Direction from the Department for Infrastructure in December 2024 confirming the draft Plan Strategy as "sound" subject to specified modifications. The Council is now preparing the Local Policies Plan, which must be consistent with the adopted Plan Strategy and will provide the detailed settlement limits, zonings and designations.
The LDP 2032 plans for the delivery of at least 9,000 new homes across the district to 2032, aligned with the Strategic Growth Plan, and includes a general requirement for 20% of new housing to be affordable. With significant new housing anticipated, including on infill and redevelopment sites at higher densities than their surroundings, the way each scheme protects neighbouring amenity becomes a key consideration.
The policy basis for daylight and sunlight
The adopted Plan Strategy operates alongside Northern Ireland's retained regional policy, which continues to set the substantive tests for residential amenity:
- The Strategic Planning Policy Statement (SPPS), 2015, which requires planning to create quality, sustainable places and to safeguard amenity.
- Planning Policy Statement 7 (PPS 7): Quality Residential Environments and its Addendum, with the companion design guide "Creating Places". PPS 7 Policy QD1 requires development to respect the amenity of existing and future residents, while "Creating Places" gives the measurable design benchmarks.
The LDP 2032 reflects these principles: it requires a clear design concept for housing and mixed-use schemes, and recognises that established residential areas, even where they lack the distinctive character of a Conservation Area or Area of Townscape Character, remain vulnerable to harm from over-intensive infill and redevelopment.
Separation distances and overshadowing in practice
"Creating Places" is the document planning officers turn to for the numerical expectations on privacy and daylight. Its principal benchmarks are:
- Around 20m between opposing rear first-floor windows of new houses on green-field and lower-density sites (paragraph 7.15).
- Where a scheme abuts the private gardens of existing properties, a separation greater than 20m with a minimum of around 10m from the rear of new houses to the common boundary (paragraph 7.16).
- For apartments with upper-floor living rooms or balconies, a separation of around 30m, or a minimum of around 15m to a common boundary with private gardens (paragraph 7.17).
- An above-eye-level boundary treatment for around 3m from the back of the house to protect privacy (paragraph 7.19).
On daylight, paragraph 7.21 advises that the building spacing needed for privacy will normally also deliver a satisfactory level of daylight and an acceptable minimum of sunlight, while paragraph 2.26 requires orientation and sun paths to be assessed at the outset so that "unreasonable obstructions to daylight and sunlight for existing buildings and spaces" are avoided. Importantly, "Creating Places" allows flexibility where it is necessary to reflect traditional building forms or protect heritage and landscape, which is directly relevant in a historic city like Derry.
Local context: the walled city and the Peace Bridge
Derry is the only remaining completely walled city in Ireland, and the Derry Walls form the largest ancient monument in state care in Northern Ireland, with the longest complete circuit of ramparts of any walled town in the country. Their setting is managed through a dedicated Conservation Plan and is sensitive to the height, massing and spacing of new buildings. The city's later landmarks, such as the 235-metre Peace Bridge linking Ebrington with the city centre, sit within a townscape where scale and openness are carefully weighed.
In and around the walled city, and in the city's Conservation Areas and Areas of Townscape Character, daylight and overshadowing issues are assessed against a backdrop of tight historic plots and tall existing buildings. Schemes that would unreasonably obstruct light to neighbouring windows, or overshadow gardens and public spaces, face close scrutiny, and a robust assessment is the best way to show that a proposal is acceptable.
How daylight and sunlight are measured
The recognised technical methodology is the Building Research Establishment guide BRE BR 209, "Site layout planning for daylight and sunlight: a guide to good practice" (2022 edition), used with the European standard BS EN 17037. The principal tests are:
- Vertical Sky Component (VSC) and the no-sky line (daylight distribution) test for daylight to neighbouring and proposed windows.
- Annual Probable Sunlight Hours (APSH) for winter and total sunlight to windows facing within 90 degrees of due south.
- Overshadowing of amenity space, usually assessed against the 21 March sunlight-on-ground criterion for gardens and shared open space.
This numerical evidence complements the qualitative separation-distance approach of "Creating Places" and is especially valuable on constrained urban sites within Derry and Strabane.
When you are likely to need a report
- Two-storey and rear extensions in established residential streets where overlooking or loss of light is raised.
- Infill and backland housing where the LDP 2032 anticipates higher-density development.
- Apartment schemes within the city, where the 30m and 15m "Creating Places" benchmarks apply.
- Development near the walls, Conservation Areas or other heritage assets where amenity and character must both be protected.
How Fortress Associates can help
Fortress Associates offers our daylight and sunlight report service to homeowners, architects and developers across Derry City and Strabane and the rest of Northern Ireland. Our reports follow BRE BR 209 (2022) and BS EN 17037 and are written to engage PPS 7 and "Creating Places" alongside the adopted LDP 2032. We work nationwide with a 4-5 working day turnaround and require no advance payment. We also produce Building Regulations drawings to the Building Regulations (Northern Ireland). To get started, please contact us.
Related reading
For a neighbouring authority, see our companion guide to daylight requirements in Causeway Coast and Glens.
Sources & further reading
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